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PubMed2004

VO2+ ions in zinc lead borate glasses studied by EPR and optical absorption techniques.

Electron paramagnetic resonance (EPR) and optical absorption spectra of vanadyl ions in zinc lead borate (ZnO-PbO-B2O3) glass system have been studied. EPR spectra of all the glass samples exhibit resonance signals characteristic of VO2+ ions. The values of spin-Hamiltonian parameters indicate that the VO2+ ions in zinc lead borate glasses were present in octahedral sites with tetragonal compression and belong to C4V symmetry. The spin-Hamiltonian parameters g and A are found to be independent of V2O5 content and temperature but changing with ZnO content. The decrease in Deltag( parallel)/Deltag( perpendicular) value with increase in ZnO content indicates that the symmetry around VO2+ ions is more octahedral. The decrease in intensity of EPR signal above 10 mol% of V2O5 is attributed to a fall in the ratio of the number of V4+ ions (N4) to the number of V5+ ions (N5). The number of spins (N) participating in resonance was calculated as a function of temperature for VO2+ doped zinc lead borate glass sample and the activation energy was calculated. From the EPR data, the paramagnetic susceptibility was calculated at various temperatures and the Curie constant was evaluated from the 1/chi-T graph. The optical absorption spectra show single absorption band due to VO2+ ions in tetragonally distorted octahedral sites.

Absorption↗
PubMed2003

Determination of pyridine and adenine nucleotide metabolites in Bacillus subtilis cell extract by sweeping borate complexation capillary electrophoresis.

With a growing interest in new areas of bioanalytical research such as metabolome analysis, the development of sensitive capillary electrophoresis (CE) methods to analyze sub-microM concentrations of analytes in biological samples is required. In this report, the application of CE with sweeping by borate complexation is used to analyze a group of seven pyridine and adenine nucleotide metabolites derived from bacteria Bacillus subtilis cell extracts. Nanomolar (nM) detectability of analytes by CE with UV photometric detection is achieved through effective focusing of large sample plug (approximately 10% of capillary length) using sweeping by borate complexation method, reflected by a limit of detections (S/N = 3) of about 2 x 10(-8) M. Changes in metabolites concentrations were observed in cell extracts when using either glucose or malate as the carbon source in the culture medium. Concentration of pyridine and adenine nucleotides in cell extracts varied widely from 78.6 (+/-7.6) microM for nicotinamide-adenine dinucleotide in malate to 0.66 (+/-0.12) microM for nicotinamide-adenine dinucleotide phosphate in glucose culture medium. Concentrations of metabolites in a single cell were also estimated at millimolar (mM) level. The method was validated in terms of linearity, sensitivity and reproducibility. The application of CE by sweeping borate complexation allows for sensitive and reproducible analyses of nucleotide metabolites in complex biological samples such as bacteria cell extracts.

Adenine Nucleotides↗
PubMed1999

Capacity gradient anion chromatography with a borate complex as eluent.

Complex formation between borate compounds and vicinal diols is well recognized. Generally, in a chemically bonded anion-exchange resin, many hydroxyl groups are introduced on the surface of the resin in order to make the resin hydrophilic. The borate as an eluting reagent also reacts to these hydroxyl groups, and this complex formation decreases the apparent ion-exchange capacity of the column by being dissociated to the anion depending on the eluent pH. In the present work a method is described for the simultaneous determination of anions based on the capacity gradient for suppressed ion chromatography. A Tosoh IC-Anion-PW column and dihydroxyphenylborane-mannitol eluent system were used. To maintain baseline stability, it was helpful to keep the borate concentration constant during a gradient of 16 to 0 mM mannitol as a modifier to prevent the complex formation with the hydroxyl on the resin. The chemical composition of the eluents and gradient profiles are discussed and the application to the analysis of the condensed phosphates with widely varying retention times as food additives in a cheese sample is presented.

Anions↗
PubMed2000

FT-IR spectroscopy of supersaturated aqueous solutions of magnesium borate.

FT-IR spectra of supersaturated aqueous solution of magnesium borate, its acidized solutions with azeotropic hydrochloric acid, and its diluted solutions with water have been recorded. The FT-IR spectra of borate in solution are obtained by difference, subtracting the FT-IR spectrum of water from that of the magnesium borate supersaturated aqueous solution. All of the results showed that various polyborate anions in the supersaturated aqueous solutions exist. The bands of symmetric pulse vibration of the corresponding polyborate anions were indicated and some assignments were tentatively given.

Borates↗
PubMed2001

Characteristics of a column suitable for capacity gradient chromatography with a borate eluent.

In capacity gradient elution, the gradient separation of ionic species is achieved by decreasing the ion-exchange capacity of a column during the course of the separation. Diol-type hydroxy groups on the resin surface form anionic complexes with borate as an eluting reagent. Thus, a chemically bonded anion-exchange column enriched with residual hydroxy groups allows the creation of a capacity gradient. An increase in the amount of the complex formed gradually brings about a decrease in the ion-exchange capacity of the column, and strongly bound analyte ions are eluted. We investigated the characteristics of a column suitable for this eluent system. The concentration of borate eluent required to remove the ion-exchange capacity depended inversely on the ratio of the residual hydroxy groups to functional groups. On a column in which this ratio was approximately 100, the ion-exchange capacity could easily be adjusted by using a low concentration of mannitol as a competing reagent. Use of this column led to very small baseline shifts during the borate-mannitol gradients, and to the simultaneous determination of anions with widely varying retention times.

Borates↗
PubMed2004

Chiral ligand exchange capillary electrophoresis using borate anion as a central ion.

Native DL-pantothenic acid, having a 1,3-diol structure, was chirally resolved by ligand exchange capillary electrophoresis using (S)-3-amino-1,2-propanediol as a chiral selector and the borate anion as a central ion. The optimum conditions for both high resolution and short migration time of DL-pantothenic acid were found to be 200 mM (S)-3-amino-1,2-propanediol and 200 mM borate buffer (pH 9.2) containing 15% methanol with an applied voltage of +25 kV at 20 degrees C, using direct detection at 200 nm. With this system, the resolution (Rs) of racemic pantothenic acid was approximately 1.7. When (S)-1,2-propanediol, (S)-1,2,3-propanetriol, (S)-1,3-butanediol or (S)-1-amino-2-propanol were used as chiral ligand instead of (S)-3-amino-1,2-propanediol, DL-pantothenic acid was not enantioseparated. When borate was replaced with Tris or butylborate, no chiral separation was achieved. Therefore, the ionic interaction between the amino and carboxyl groups of the ternary complex may play an important role in the enantioseparation of DL-pantothenic acid by the proposed CE system.

Anions↗
PubMed1996

Rhamnogalacturonan-II, a pectic polysaccharide in the walls of growing plant cell, forms a dimer that is covalently cross-linked by a borate ester. In vitro conditions for the formation and hydrolysis of the dimer.

Rhamnogalacturonan II (RG-II) is a structurally complex pectic polysaccharide present in the walls of growing plant cells. We now report that RG-II, released by endopolygalacturonase treatment of the walls of suspension-cultured sycamore cells and etiolated pea stems, exists mainly as a dimer that is cross-linked by a borate ester. The borate ester is completely hydrolyzed at room temperature within 30 min at pH 1, partially hydrolyzed between pH 2 and 4, and stable above pH 4. The dimer is formed in vitro between pH 2.4 and 6. 2 by treating monomeric RG-II (0.5 mM) with boric acid (1.2 mM); the dimer formed after 24 h at pH 3.4 and 5.0 accounts for approximately 30 and approximately 5%, respectively, of the RG-II. In contrast, the dimer accounts for approximately 80 and approximately 54% of the RG-II when the monomer is treated for 24 h at pH 3.4 and 5.0, respectively, with boric acid and 0.5 m Sr2+, Pb2+, or Ba2+. The amount of dimer formed at pH 3.4 or 5.0 is not increased by addition of 0.5 mM Ca2+, Cd2+, Cu2+, Mg2+, Ni2+, and Zn2+. Steric considerations appear to regulate dimer formation since those divalent cations that enhance dimer formation have an ionic radius >1.1 A. Our data suggest that the borate ester is located on C-2 and C-3 of two of the four 3'-linked apiosyl residues of dimeric RG-II. Our results, taken together with the results of two previous studies (Kobayashi, M., Matoh, T., and Azuma, J.-I. (1996) Plant Physiol. 110, 1017-1020; Ishii, T., and Matsunaga, T. (1996) Carbohydr. Res. 284, 1-9) provide substantial evidence that this plant cell wall pectic polysaccharide is covalently cross-linked.

Barium↗
PubMed2004

Sensory and associated reactions to mineral dusts: sodium borate, calcium oxide, and calcium sulfate.

Occupational exposure limits (OELs) for irritant dusts have had no quantifiable bases. This study (1) charted chemosensory feel, denoted chemesthesis here, to dusts of calcium oxide (1 to 5 mg/m(3)), sodium tetraborate pentahydrate [sodium borate] (5 to 40 mg/m(3)), and calcium sulfate (10 to 40 mg/m(3)); (2) examined correlates of the chemesthetic sensations; and (3) sought to illuminate the basis for potency. Twelve screened men exercised against a light load while they breathed air in a dome fed with controlled levels of dust for 20 min. Measured parameters included nasal resistance, nasal secretion, minute ventilation, heart rate, blood oxygenation, mucociliary transport time, and chemesthetic magnitude, calibrated to pungency of carbon dioxide. Subjects registered time-dependent feel from exposures principally in the nose, secondarily in the throat, and hardly in the eyes. Calcium oxide had the greatest potency, followed by sodium borate, with calcium sulfate a distant third. Of the physiological parameters, amount of secretion showed the best association with chemesthetic potency. That measure, as well as mucociliary transport time and minute ventilation, went into calculation of mass of dust dissolved into mucus. The calculations indicated that the two alkaline dusts increased in equal molar amounts with time. At equal molar concentrations, they had, to a first approximation, equal chemesthetic magnitude. On the basis of mass concentration in air or dissolved into mucus, calcium oxide and sodium borate differed in potency by a factor just above five, equal to the difference in their molecular weights. This relationship could inform the setting of OELs for a critical effect of irritation.

Adolescent↗
PubMed1976

Hybridization of glyceraldehyde-3-phosphate dehydrogenase in borate.

Conditions for the hybridization of glyceraldehyde-3-phosphate dehydrogenase (GPD) [EC 1.2.1.12] in the presence of dilute borate were examined with horseshoe crab and rabbit GPDs. Hybridization was strongly dependent upon pH, borate concentration, and temperature. The optimum medium for hybridization was 10mM Tris-HCl-1 mM 2-mercaptoethanol-1mM EDTA containing 10-20 mM borate, pH 8.5-9.0. Hybridization was performed by incubation of two electrophoretically distinct GPDs at 30 degrees for 3-15 hr in the above medium at a protein concentration of 1-2 mg/ml. The time course of hybridization was analyzed under the optimized conditions. Symmetrical A2B2-type hybrid appeared only 5 min after incubation for 1 hr. Hybridization of GPDs from 7 different species was examined under the optimal conditions. Hybridization was detected with rabbit-horseshoe crab, yeast-rabbit, yeast-chicken, and chicken-horseshoe crab combinations. Subunit-subunit interaction, the mechanism of hybridization, and the structure of GPD are discussed based on the results obtained.

Animals↗
PubMed1986

Antimicrobial activity of borate-buffered solutions.

A minimal salts medium adjusted to physiological pH and osmolality was buffered with either 0.3% phosphate or 1.2% borate and evaluated for antimicrobial activity. The borate-buffered medium, either with or without a carbon source, exhibited significant antimicrobial activity against 15 Pseudomonas strains, 12 strains of enteric bacteria, and 7 strains of staphylococci. The borate-buffered system appears suitable for use as a generic vehicle for ophthalmic pharmaceutical agents.

Anti-Bacterial Agents↗
PubMed1994

Reproductive effects of sodium borates on male employees: birth rate assessment.

OBJECTIVES: The purpose of the study was to investigate potential reproductive effects of sodium borates on occupationally exposed male employees at a large mining and production facility in the Mojave Desert of California. METHODS: The standardised birth ratio (SBR) was used to assess fertility of the male employees. Live births were the measured end point, and the rate of female to male offspring was also assessed. Data were collected through a questionnaire after a series of on site introductory and explanatory meetings with the employees. Initial non-responders were followed up by telephone. Medical insurance records were assessed for those who declined to participate. RESULTS: The questionnaire was a good method of ascertainment for live births. There was no evidence of selection bias in the results. There was a highly significant excess of offspring fathered by the male employees. There was no evidence of a relation between exposure and this excess of offspring, nor were there any temporal differences during the period of observation (> 30 years). Also, there was an excess of the percentage of female offspring fathered by these male employees. This excess of female offspring was not significant. There was no evidence of an exposure relation to sodium borates with this excess of female offspring nor were there any temporal differences. CONCLUSION: Under the conditions studied, there were no adverse reproductive effects of high borate doses as reported from oral ingestion studies in animals.

Adult↗
PubMed1994

Acute and chronic respiratory effects of sodium borate particulate exposures.

This study examined work-related chronic abnormality in pulmonary function and work-related acute irritant symptoms associated with exposure to borate dust in mining and processing operations. Chronic effects were examined by pulmonary function at the beginning and end of a 7-year interval. Time-specific estimates of sodium borate particulate exposures were used to estimate cumulative exposure during the study interval. Change in pulmonary function over the 7 years was found unrelated to the estimate of cumulative exposure during that interval. Exposure-response associations also were examined with respect to short-term peak exposures and incidence of five symptoms of acute respiratory irritation. Hourly measures of health outcome and continuous measures of particulate exposure were made on each subject throughout the day. Whenever a subject reported one of the irritant symptoms, a symptom intensity score was also recorded along with the approximate time of onset. The findings indicated that exposure-response relationships were present for each of the specific symptoms at several symptom intensity levels. The associations were present when exposure was estimated by both day-long and short-term (15-min) time-weighted average exposures. Associations persisted after taking account of smoking, age, and the presence of a common cold. No significant difference in response rate was found between workers exposed to different types of sodium borate dusts.

Adult↗
PubMed2003

Low frequency of infertility among workers in a borate processing facility.

In order to rule out the possibility of omitting some individuals in the study at field visits described in previous articles, either because of the reluctance of the subject or because of his appointment elsewhere, fertility and infertility states of borate workers of the Borax and Acid Plants in Bandirma, Balikesir are given. Balikesir is one of the four provinces with large borate deposits of Turkey, and Bandirma is 1 of its 19 districts. This county is relatively far away from borate deposits, and drinking water piped out through the springs has a boron amount between 0.10 and 0.82 ppm B. That the participants are occupationally exposed to the mineral in essence is therefore conceivable. At the first phase of the investigation, 191 workers were interviewed, as detailed previously. Among these, there were six infertiles of the primary type with a rate 3.1%. Boron-unrelated infertile couples among sibs were found to be 2.6-3.6%, and 3.2% for three generation marriages-none being higher than those revealed in different sets of controls. In the second stage of work, computerized files of all workers of the facility and all employees of the general management sharing the same location were checked without an interview. Twenty-four subjects (3.4%) out of 712 workers were childless versus 2.7% among 108 employees, and 2.2% among 91 workers of a distantly located sulfuric acid plant of the same complex. The differences were not significant, and these recent findings support the conclusion already reached almost unambiguously that boron exposure at the present levels does not interfere with human reproduction.

Air Pollutants, Occupational↗
PubMed2006

Chiral separation of synthetic vicinal diol compounds by capillary zone electrophoresis with borate buffer and beta-cyclodextrin as buffer additive.

The investigation on capillary electrophoretic enantioseparation of six synthetic compounds containing vicinal diol groups has been undertaken to acquire the optimum conditions using native beta-cyclodextrin (beta-CD) as chiral selector and borate as a background electrolyte. The separation was carried out in an uncoated capillary (58.5 cm x 75 microm i.d., effective length 48.5 cm) and the effects of several important factors were investigated in detail. The results showed that beta-CD as a chiral selector exhibited good enantioselectivity and that the enantioseparation was greatly influenced by the structure of the diols, the borate concentration and the buffer pH. The optimum performance was obtained for the chiral vicinal diols under the conditions of 200 mM borate buffer of pH 9.8 containing 1.7% beta-CD at an applied voltage of 15 kV and a capillary temperature of 20 degrees C. Under the conditions, four diols were baseline separated with fast analysis time and the good theoretical plate numbers (above 10 x 10(4)) and favorable migration-time reproducibilities (RSDs below 3.0%) were obtained. The separation results were satisfactory.

Borates↗
PubMed1976

The influence of borate and calcium on the gel formation of a sulfated polysaccharide from Ulva lactuca.

The water-soluble, sulfated polysaccharide isolated from Ulva lactuca, forms a soft gel when dialysed against sea-water, provided the polysaccharide concentration is 1% or higher and the pH above 7.5. The components of sea-water needed for this gel formation are boric acid and calcium ions. At concentration normally found in sea-water, neither borate nor calcium ions alone produce a gel. It is assumed that the gel formation involves the formation of borate-polysaccharide complexes leading to intermolecular linkages which are stabilized by calcium ions in an unknown manner. This assumption is supported by experiments with extraction of this polysaccharide from the dry seaweed and by the results obtained with the isolated polysaccharide. Agreement between these experiments leads to the conclusion that the sulfated polysaccharide (in vivo) most probably occurs as a gel stabilized by the borate and calcium ions in sea-water.

Borates↗
PubMed1976

[Urinary mercury excretion in professional users of an antiseptic soap containing 0,04% phenylmercury borate].

Concentrations of mercury and of creatinine were measured under blind conditions in 84 samples of urine from 48 regularly using a liquid soap containing 0.04% phenylmercuric borate plus 3% hexachlorophene for hand disinfection ("users"), and in 138 urine samples of 80 subjects disinfecting their hands with a soap containing only hexachlorophene ("controls"). The concentration of mercury in the urine of users was 27+/-3 mug/1 (mean +/- SE), and in controls 8+/-1 mug/1; calculated total 24 h urinary mercury excretions were 27+/-2 mug/24 h users and 9+/-1 mug/24 h in controls. Women excreted slightly more mercury than men both in the user group and the control group. In both controls and users from whom a second urine sample was obtained after a 2-week interval the concentration of mercury was consistently lower in the second sample. No correlation was found between urinary excretion of mercury and frequency of handwashings or reported intake of mercury-containing food. No difference was found in the numbers of different types of urinary cells or urine pH as between users and controls. It is concluded 1) that regular hand disinfection with a liquid soap containing 0.04% phenylmercuric borate enhanced urinary excretion of mercury indicating an increase in total daily absorption of 30-100 mug Hg/24 h, 2) that the absorption of mercury from the phenylmercuric borate-containing soap occurred partly by transfer from the hands to the oral cavity, 3) that, though nontoxic in themselves, the additional amounts of mercury absorbed through the use of mercury contained in skin disinfectants are potentially dangerous due to as yet unknown interactions with other toxic or pathogenic factors.

Borates↗
PubMed1988

The effects of sodium borate and sodium bicarbonate upon fluoride retention and serum calcium and phosphate in sheep.

Six sheep were each given a fluoride slow-release intra-ruminal capsule which delivered 30 +/- 1.02 mg F/d. After 20 days, fluoride balance studies were carried out for four days and serum fluoride measured daily. Each sheep was then given 23.1 mg sodium borate daily via drench gun for six days, and the balance studies continued. In a separate similar experiment, six sheep were given capsules which released 66.4 +/- 4.2 mg F/d, and 25 ml of 25 g/L sodium bicarbonate was administered half-hourly over four hours, 14 days after capsule administration. Urinary pH was also measured. Sodium borate treatment increased fluoride output, mainly in the faeces, and temporarily reduced serum fluoride concentration. Serum phosphate fell during sodium borate administration, while serum calcium was unaffected. Sodium bicarbonate reduced serum fluoride concentration over the three days, and fluoride output was increased, mainly via the urine, while urinary pH was largely unaffected. Serum calcium and phosphate were temporarily affected to a small extent.

Animals↗
PubMed1994

A modified hot borate method significantly enhances the yield of high-quality RNA from cotton (Gossypium hirsutum L.).

The isolation of biologically active RNA from cotton (Gossypium hirsutum L.) is difficult due to interference by high levels of endogenous phenolics, polysaccharides, and secondary metabolites. A modified hot borate procedure was developed to combat these cellular constituents during tissue homogenization, resulting in the quantitative recovery of RNA suitable for hybridization analysis, in vitro translation, and cDNA synthesis. The efficacy of several hot borate buffer adjuvants for the qualitative and quantitative recovery of leaf RNA was monitored by absorbance spectra, gel electrophoresis, protein, and cDNA synthesis. Of the buffer adjuvants evaluated, polyvinylpyrrolidone-40 (PVP-40) exhibited the single, most significant impact on the yield and quality of RNA isolated from cotton leaves, although inclusion of deoxycholate and/or Nonident-40 (NP-40) further enhanced the quality of the RNA. The unsurpassed qualitative and quantitative recovery of total RNA from cotton by hot borate buffer at alkaline pH, supplemented with PVP-40, deoxycholate, and/or NP-40 had also proven satisfactory for other recalcitrant plant species as well as for especially difficult tissue types.

Boric Acids↗